Debounce

Handle a burst of updates once using its latest event.

Works withDurable workflows Durable endpoints

Wait until a user stops editing a record, then process only the latest update. Each matching event restarts the quiet period for its key, so the function runs once for the burst.

debounce: { period: "2s", timeout: "5s" }

Simulator

Event
Replaced by a later event
Waiting for a quiet period
Step executing
Completed

Each event restarts the 2s quiet period and replaces the pending event. The first burst settles, so a run starts with event 3. The steady stream never settles, so the 5s timeout starts a run with the latest event, 10.

Configure a quiet period

This TypeScript v4 function waits five minutes after the most recent company/updated event for an account. Each new event for that account restarts the five-minute wait. The optional ten-minute timeout stops a continuous stream from postponing the run indefinitely.

import { Inngest } from "inngest";

const inngest = new Inngest({ id: "customer-sync" });

export const syncCompany = inngest.createFunction(
  {
    id: "sync-company",
    triggers: { event: "company/updated" },
    debounce: {
      key: "event.data.account_id",
      period: "5m",
      timeout: "10m",
    },
  },
  async ({ event, step }) => {
    await step.run("process-latest-update", async () => {
      console.log(event.data.account_id);
    });
  }
);

Replace the step body with your application work. The handler receives the last event in the burst, not the first event and not an array of every event.

The optional key is a Common Expression Language (CEL) expression string evaluated against each event. Each unique value gets an independent debounce period. In the example, updates for two accounts can settle and run separately. Without a key, matching events share the function's debounce period.

How the wait changes

The first matching event starts a debounce period.
Another matching event within that period restarts the wait. The new event replaces the pending one.
When the full period passes with no new matching event, Inngest starts one run using the last event received.
If you set timeout, Inngest stops extending the wait once that maximum time passes and runs with the latest event. The next matching event starts a new debounce period.

Choose the right behavior

Need	Use	Which event runs?
Wait for updates to stop, then use the latest state	Debounce	The last event in the burst
Start work when an event arrives and skip events beyond a limit	Rate limiting	An event admitted under the limit

Debounce delays the run. Rate limiting does not wait for a quiet period. If you need to process every event, neither behavior fits; consider throttling, which queues excess runs.

Configuration and limits

Option	Meaning
`period`	Required quiet period. TypeScript v4 permits `1s` through `7d` (`168h`).
`key`	Optional CEL expression that creates a separate debounce period per value.
`timeout`	Optional maximum time that incoming events can keep extending the wait.

Debounce cannot be combined with batching. Debounce keeps one latest event; batching collects multiple events for one run.